Hydraulic Characteristics of Emerged Rigid and Submerged Flexible Vegetations in the Riparian Zone

Abstract

Flow resistance, velocity distribution, and turbulence intensity are significantly influenced by aquatic vegetations (AV) in riparian zones. Understanding the hydraulics of flow with planted floodplains is of great significance for determining the velocity distribution profile and supporting the fluvial processes management. However, the traditional flume experiment method is inefficient. Therefore, the multigroup simultaneous flume test method was carried out to describe the flow patterns affected by emerged rigid (reed and wooden stick) and submerged flexible vegetations (grass and chlorella). The Acoustic Doppler Velocimeter (ADV) was utilized to measure the velocity at one point for different experimental conditions. The results showed that hydraulic features were influenced by different types of vegetation. Furthermore, the relative depth (z/h) was a determining factor of those variations. In addition, the time-averaged velocity distributions of planted floodplains are not logarithmic. Instead, they represented “s-shape” profiles. In detail, for the vegetated floodplains, reed and wood followed an s-shape profile, but for grass and chlorella, they followed reverse s-shape profile. For all cases, turbulence is not isotropic and the change law of turbulence intensity is different in different sections. The flow resistance, turbulence intensities, and Reynold stresses influenced by different types of vegetation were also analyzed.

Investigation of the Influence of Reed Vegetation on the Hydraulic Characteristics of the Huai River Inflow Channel

“…The experimental results indicate that the reed belt along the riverbank has, to some extent, affected the flood discharge of the river, leading to an increase in the upstream water level. Meng et al [31] used multiple sets of synchronous water tank test methods to describe the flow patterns influenced by the emergence of rigid vegetation and submerged flexible vegetation. The velocity of a certain point under different experimental conditions is measured using an acoustic Doppler velocimeter (ADV).…”

Analysis of the Possibility of Management of Curly-Leaf Pondweed for Energetic Purposes

“…Eutrophication of lakes is the phenomenon of increased abundance of organic matter in the reservoir, causing its fertilization [5][6][7]. The intensification of the eutrophication phenomenon in lakes manifests, among other factors, as increased phytoplankton bloom [8,9], development of submerged vegetation [10,11] and decreased water transparency [12,13]. The process of eutrophication of lakes, its causes and effects, and ways to counteract it have been widely described in limnological literature [14][15][16][17][18].…”